UCSB Science Line
Sponge Spicules Nerve Cells Galaxy Abalone Shell Nickel Succinate X-ray Lens Lupine
UCSB Science Line
Home
How it Works
Ask a Question
Search Topics
Webcasts
Our Scientists
Science Links
Contact Information
What solids go through sublimation?
Answer 1:

You may already know that are three main “states” of matter: gases, liquids, and solids (there are really four, but that is besides the point). Your question is asking which solids undergo the solid-to-gas transition, sublimation.

Whether or not a solid will sublime depends on a number of factors. Sometimes, a solid will favor going to the liquid state before the gaseous state and other times a chemical reaction will occur before the temperature can be raised high enough to get the original molecules in the gas state. There is a subject called thermodynamics that allows us to find the temperatures at which solids will turn into liquids and gases and the temperatures at which chemical reaction can occur. If a chemical reaction does not occur and the liquid state is not favored over the gas state as you raise the temperature, the solid will sublime.

Consider a couple of solids: ice, which is made out of water molecules, dry ice, made from carbon dioxide molecules, and wood, made from cellulose molecules.

First, imagine we take a piece of ice and set it outside on a sunny day. We notice that the ice begins to melt and eventually all we have left is a pool of water. If we wait even longer we see that the pool of water has disappeared.

Essentially, ice prefers to change into the liquid state first before evaporating into the gaseous state. (*Note this is not completely true! Even ice and snow sublime to a certain extent before changing in the liquid state!) Now imagine we take a piece of dry ice and lay it outside on a sunny day. If you’re not sure what dry ice is, you might want to youtube dry ice. In this case we see that the dry ice begins to vaporize directly from the solid state!

Finally, we lay the wood outside on a sunny day. Nothing happens of course and, being the scientists we are, we decide that we must heat the wood even more to try to make it into a gas. However, as soon we heat the wood, for instance with a match or a lighter, we see that the wood catches fire. This is an example of a chemical reaction, where cellulose molecules in the wood and actually being converted into among other things, carbon dioxide, the stuff of dry ice and what we breathe out.

Examples of solids that sublime are dry ice (solid carbon dioxide), iodine, arsenic, and naphthalene (the stuff mothballs are made of). This is a great question that is more difficult to answer than you would suspect. If you are interested in learning more, please free to ask.

Best,

Answer 2:

Any solid may be sublimed if its temperature and pressure are below its triple point. For example, if you were to freeze water into ice and cool it further and then reduce the pressure, you could get ice to sublime. Some other examples include: Dry ice (solid CO2) which sublimes at atmospheric pressure and -78 C, and C60 (buckyballs) which sublimes at atmospheric pressure at around 800 K.


Answer 3:

Some common solids go through sublimation at standard pressure (1 atmosphere). Carbon dioxide sublimates at -78.5 °C (-109.3 °F), and we use this “dry ice” for cooling purposes. Iodine is another substance that has been observed to sublimate at room temperature and pressure. Naphthalene, a chemical with numerous applications, sublimates at approximately 80 °C (176 °F). A substance which normally doesn’t sublimate (i.e. water) at standard pressure can be made to sublimate at lower pressures. The phase relationships of a chemical are expressed on a phase diagram with pressure and temperature as the two axes.


Answer 4:

A number of solids are capable of sublimating at normal temperatures and pressures, including snow, iodine, arsenic, and solid carbon dioxide (dry ice). Sometimes other materials can be made to sublimate by creating low pressure conditions.

If you take a materials science class in the future (probably in college), then you will learn to read "phase diagrams," which are basically graphs that show what temperatures and pressures are required to have solid, liquid or gas phases for a material. You can see from these diagrams whether or not there is an available transition directly from solid to gas for any material. This tells you whether or not a material is capable of sublimating.


Answer 5:

Almost all solids can go through sublimation, under certain conditions. This just means the solids go straight to gasses without becoming liquids first. Typically solids undergo sublimation at low pressures (under vacuum). At standard, atmospheric pressure, a few solids which will sublime are iodine (at slightly higher than room temperature), carbon dioxide (dry ice) at -78.5 degrees Celsius, as well as naphthalene (used in mothballs) and arsenic.


Answer 6:

All solids sublime. The rate of sublimation depends on temperature, air pressure, and the solid in question. Water ice is the one that we think of that sublimes most readily.



Click Here to return to the search form.

University of California, Santa Barbara Materials Research Laboratory National Science Foundation
This program is co-sponsored by the National Science Foundation and UCSB School-University Partnerships
Copyright © 2015 The Regents of the University of California,
All Rights Reserved.
UCSB Terms of Use